Polymer particles containing cationic groups, for example, for use as mordants in an image-receiving layer of inkjet recording elements, in order to mordant dye-based inks are generally well known in the art. U.S. Pat. Nos. 6,045,917 and 6,645,582, for example, disclose water-insoluble cationic polymeric particles having at least about 20 mole percent of a cationic mordant moiety. Preferred mordants comprising a polymer having a vinylbenzyl trimethyl quaternary ammonium salt moiety are disclosed. U.S. Pat. No. 6,645,582 states that such particles can be core/shell particles wherein the core is organic or inorganic and the shell in either case is a cationic polymer (page 3, lines 44 to 58).
U.S. Pat. No. 6,619,797 discloses an image-receiving layer comprising a cationic core/shell particle prepared by emulsion polymerization containing at least one ethylenically unsaturated monomer containing a trialkylammonium salt. However, the shell, but not the core, contains the trialkylammonium group.
U.S. Pat. No. 6,492,006 discloses an inkjet recording element comprising a support having thereon an image receiving layer comprising at least about 70% by weight of porous polymeric particles, the particles having a core/shell structure comprising a porous polymeric core covered with a shell of a water-soluble polymer. The core-shell particles are formed by emulsion polymerization of the core monomers in the presence of the shell polymer. The recording element exhibited less cracking, but no improvement in dye density was disclosed. The porous polymeric particles do not have a monomer with cationic functionality, thus do not function as mordant.
US 2005/0031806 discloses a composition for forming an ink accepting layer comprising a structured cationic core/shell latex (TruDot DPX, Westvaaco), wherein a non-porous core does not have a cationic functional group and does not expand, and the shell contains a cationic functional group capable of expansion by an acid. The recording element exhibited improved absorption and water-fastness, but no improvement in dye fade was disclosed.
U.S. Pat. No. 6,818,685 discloses a coating composition comprising a non-ionic latex polymer (polyvinyl acetate), wherein the polyvinyl acetate has a core and a shell, and the shell comprises poly(vinyl alcohol). The particle core has no positive ionic character. A composition of high solids and low viscosity was disclosed and the recording element exhibited reduced dusting, but no improvement in dye fade was disclosed.
U.S. Pat. No. 6,969,445 and U.S. Pat. No. 6,669,815 describe graft copolymers of poly(vinyl alcohol) with cationic polymers.
Other uses for cationic core-shell particles are known. For example, such particles are useful in ink compositions. Another area of use for such particles is in paints and other coatings. Still another area of use is in drug delivery, for example, delayed release drug delivery. Still other uses include toughening agents for polycarbonates (El-Aasser et al. Macromol. Symp. 101, 517-529, 1996) and epoxies (Qian et al. Polymer Volume 38, Number 1, 1997).